Unified description of compressive modulus revealing multiscale mechanics of living cells

How to accurately characterize the modulus of living cells at the whole-cell level with a well-defined measurement geometry and precise mathematical modeling of viscoelastic relaxation is an ongoing challenge in biophysics and mechanobiology. Here, we report combined atomic-force-microscopy (AFM) measurements of stress relaxation and indentation force for 10 cell types ranging from epithelial, muscle, and neuronal cells to blood and stem cells, from which we obtain a unified quantitative description of the compressive modulus E(t) of individual living cells. The cell modulus E(t) is found to have an initial exponential decay at short times t followed by a long-time power-law decay together with a persistent modulus. The three components of E(t) at different timescales thus provide a digital spectrum of mechanical readouts that are closely linked to the hierarchical structure and active stress of living cells. This work provides a reliable experimental framework that can be utilized to characterize the mechanical state of living cells and investigate their physiological functions and diseased states.

Automated summary

The study used atomic force microscopy to measure the compressive modulus of 10 different types of cells, revealing characteristic decays at different time scales and their close connection to the structure and active stress of cells.